Sodium triacetoxyborohydride → 4-(2-(2-ethyl-1H-benzo[d]imidazol-1-yl)-9-methyl-8-((3-(1,1-dioxo-thiomorpholino)azetidin-1-yl)methyl)-9H-purin-6-yl)morpholine

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Reaction Steps

A mixture of 2-(2-ethylbenzoimidazol-1-yl)-9-methyl-6-morpholin-4-yl-9H-purine-8-carbaldehyde (1.2 g, 3.07 mmol), 4-azetidin-3-ylthiomorpholine-1,1-dioxide (640 mg, 3.37 mmol) and 4 Å powdered molecular sieves (2.5 g) in DCE (65 mL) was stirred at room temperature for 6.5 h before the addition of sodium triacetoxyborohydride (1.3 g, 6.13 mmol). The reaction mixture was stirred for 18 h then filtered through celite, washing with DCM. The organic phase was washed with brine (×1) and concentrated in vacuo. The organic phase was dried (Na2SO4) and concentrated in vacuo. The resulting residue was purified by column chromatography (Si—PCC, MeOH:EtOAc, 0-10%). A mixture of the resulting yellow powder and 3-mercaptopropyl ethyl sulphide silica (250 mg) was stirred in a mixture of EtOH and DCM at 50° C. for 3 h. The mixture was filtered and concentrated in vacuo. The resulting oil was loaded onto an Isolute® SCX-2 cartridge which was washed with EtOH and the product eluted with 2M NH3/EtOH. The resulting oil was triturated with Et2O and dried in vacuo at 60° C. affording 354 as a pale yellow solid (1.26 g, 73%). LCMS (Method I): RT 2.43 min [M+H]+ 566.3. 1H NMR (CDCl3, 400 MHz): δ 8.02-7.97 (m, 1 H); 7.77-7.73 (m, 1 H); 7.29-7.22 (m, 2 H); 4.34 (m, 4 H); 3.89-3.80 (m, 9 H); 3.59 (m, 2 H); 3.39-3.23 (m, 3 H); 3.12-3.04 (m, 6 H); 2.85 (m, 4 H) and 1.44 (t, J=7.5 Hz, 3 H)

Provenance & Evidence